/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.antgroup.geaflow.common.utils;

import com.google.common.base.Joiner;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

public class FileUtil {

    public static String concatPath(String baseDir, String fileName) {
        if (baseDir == null || fileName == null) {
            throw new NullPointerException();
        }
        if (baseDir.endsWith("/")) {
            return baseDir + fileName;
        }
        return baseDir + "/" + fileName;
    }

    public static String constitutePath(String... args) {
        return File.separator + Joiner.on(File.separator).join(args);
    }

    public static String getContentFromFile(String filePath) {
        File file = new File(filePath);
        if (file.exists()) {
            StringBuilder content = new StringBuilder();
            String line;
            try (BufferedReader reader = new BufferedReader(
                new InputStreamReader(new FileInputStream(file)))) {
                while ((line = reader.readLine()) != null) {
                    content.append(line).append(System.lineSeparator());
                }
            } catch (IOException e) {
                throw new RuntimeException("Error read file content.", e);
            }
            return content.toString();
        }
        return null;
    }
}
